Field of the Invention
Description of the Related Art
It is known to use intra-aortic balloon pumps, operating in counterpulsation, to assist heart function. However, intra-aortic balloon pumps may be insufficient to sustain hemodynamics if the left heart is severely injured. There have accordingly been a number of alternative devices developed for assisting heart function in patients with chronic heart failure. For example, U.S. Pat. No. 7,347,811 which issued on Mar. 25, 2008 to Peters et al., and the full disclosure of which is incorporated herein by reference, discloses a device for providing counter-pulsation heart assist by deforming the aorta. In a preferred embodiment, the deformation pressure is applied cyclically, preferably in synchrony with the diastolic period of the heart. The deformation pressure may be applied to the outer wall of the aorta or to a patch covering a resected opening in the wall of the aorta. There however remains a need for improved ventricular assist devices.